ruby: improved support for functional accesses

This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.

1 files changed, 42 insertions, 11 deletions

diff --git a/src/mem/protocol/MESI_CMP_directory-msg.sm b/src/mem/protocol/MESI_CMP_directory-msg.sm
index 67619f075..473012c61 100644
--- a/src/mem/protocol/MESI_CMP_directory-msg.sm
+++ b/src/mem/protocol/MESI_CMP_directory-msg.sm
@@ -35,11 +35,9 @@ enumeration(CoherenceRequestType, desc="...") {
   GETS,      desc="Get Shared";
   GET_INSTR, desc="Get Instruction";
   INV,       desc="INValidate";
-  PUTX,      desc="replacement message";
+  PUTX,      desc="Replacement message";
 
   WB_ACK,    desc="Writeback ack";
-  WB_NACK,   desc="Writeback neg. ack";
-  FWD,      desc="Generic FWD";
 
   DMA_READ, desc="DMA Read";
   DMA_WRITE, desc="DMA Write";
@@ -47,14 +45,14 @@ enumeration(CoherenceRequestType, desc="...") {
 
 // CoherenceResponseType
 enumeration(CoherenceResponseType, desc="...") {
-  MEMORY_ACK,  desc="Ack from memory controller";
-  DATA,      desc="Data";
-  DATA_EXCLUSIVE,      desc="Data";
-  MEMORY_DATA,    desc="Data";
-  ACK,            desc="Generic invalidate ack";
-  WB_ACK,            desc="writeback ack";
-  UNBLOCK,         desc="unblock";
-  EXCLUSIVE_UNBLOCK,         desc="exclusive unblock";
+  MEMORY_ACK, desc="Ack from memory controller";
+  DATA, desc="Data block for L1 cache in S state";
+  DATA_EXCLUSIVE, desc="Data block for L1 cache in M/E state";
+  MEMORY_DATA, desc="Data block from / to main memory";
+  ACK, desc="Generic invalidate ack";
+  WB_ACK, desc="writeback ack";
+  UNBLOCK, desc="unblock";
+  EXCLUSIVE_UNBLOCK, desc="exclusive unblock";
   INV, desc="Invalidate from directory";
 }
 
@@ -70,6 +68,21 @@ structure(RequestMsg, desc="...", interface="NetworkMessage") {
   int Len;
   bool Dirty, default="false",  desc="Dirty bit";
   PrefetchBit Prefetch,         desc="Is this a prefetch request";
+
+  bool functionalRead(Packet *pkt) {
+    // Only PUTX messages contains the data block
+    if (Type == CoherenceRequestType:PUTX) {
+        return testAndRead(Address, DataBlk, pkt);
+    }
+
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check on message type required since the protocol should
+    // read data from those messages that contain the block
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 // ResponseMsg
@@ -82,4 +95,22 @@ structure(ResponseMsg, desc="...", interface="NetworkMessage") {
   bool Dirty, default="false",  desc="Dirty bit";
   int AckCount, default="0",  desc="number of acks in this message";
   MessageSizeType MessageSize,  desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    // Valid data block is only present in message with following types
+    if (Type == CoherenceResponseType:DATA ||
+        Type == CoherenceResponseType:DATA_EXCLUSIVE ||
+        Type == CoherenceResponseType:MEMORY_DATA) {
+
+        return testAndRead(Address, DataBlk, pkt);
+    }
+
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // No check on message type required since the protocol should
+    // read data from those messages that contain the block
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }